A more precise look at fatty acids in feedstuffs

Editor’s note: The following column was provided by Dairyland Labs in Arcadia, Wis.

In previous articles for the Nutritionist e-Network newsletter, we discussed the differences in fat analysis by Ether Extract (EE) and Total Fatty Acids by Gas Chromatography (GC). Mainly, we’ve pointed out that Ether Extract includes some non-fat components like glycerol, chlorophyll, and urea. Another major advantage of GC is that we can obtain information about the individual fatty acids within a feedstuff.

These individual fatty acids have varying effects on rumen microbes. In general, the more unsaturated fatty acids we add to a lactating diet, the more likely we are to cause milkfat depression. The degree of unsaturation can also be an indicator of how rumen-friendly a fatty acid will be.

With an improved fatty acid reference method (GC) and advances in NIR calibration software, we can now predict monounsaturated (MUFA), polyunsaturated (PUFA), and rumen unsaturated (RUFA) fatty acids very accurately by NIR. While most ration-balancing programs do not currently have inputs for these fatty acid groups, understanding the fatty acid profiles of individual feedstuffs can help nutritionists and producers understand why particular feeds increase the risk of milkfat depression.

Look for the addition of MUFAs, PUFAs, and RUFAs to your distiller’s reports in January and additional advancements in fat analyses from Dairyland Laboratories Inc. in spring 2012.

* Please note, it may be worth double checking your ration balancer fatty acid calculation as the traditional EE-1 does not apply to distillers grains, and for model users TFA% of EE should be 95-100 percent.